数组模拟队列(看到很少有人用数组模拟)

#include <iostream>
#include <cstring>
using namespace std;
const int N = 2010, M = 10010;
int d[N], g[10000010], ne[M], h[N], e[M], w[M], cnt[N];
bool st[N];
int tt = -1, hh, n, m, idx;
void add(int x, int y, int z) {
    e[idx] = y, ne[idx] = h[x], w[idx] = z, h[x] = idx ++;
}
bool spfa() {
    for(int i = 1; i <= n; i++) {
        g[++ tt] = i;
        st[i] = 1;
    }
    while(tt >= hh) {
        int p = g[hh ++];
        st[p] = 0;
        for(int i = h[p]; i != -1; i = ne[i]) {
            int k = e[i];
            if(d[k] > d[p] + w[i]) {
                d[k] = d[p] + w[i];
                cnt[k] = cnt[p] + 1;
                if(cnt[k] >= n) {
                    return true;
                }
                if(!st[k]) {
                st[k] = 1;
                g[++ tt] = k;
                }
            }

        }
    }
    return false;
}
int main() {
    memset(h, -1, sizeof h);
    scanf("%d%d", &n, &m);
    while (m --) {
        int a, b, c;
        scanf("%d%d%d", &a, &b, &c);
        add(a, b, c);
    }
    if(spfa()) {
        puts("Yes");
    }
    else {
        puts("No");
    }
    return 0;
}